1. Field
One or more embodiments of the present invention relate to a secondary battery.
2. Description of the Related Art
Secondary batteries have been esteemed as power sources for a variety of electronic and communication devices as they are rechargeable and portable.
In typical secondary batteries, electrode plates and separators are alternately stacked, or a stacked and wound-type electrode assembly is mounted in a case. In this case, an electrode tab is attached to the electrode plate of the electrode assembly, and an end portion of the electrode tab outwardly protrudes when the electrode assembly is mounted in the case. The electrode tab protruding from the case is electrically connected to an external electrode lead.
Here, leakage may occur from a contact portion with an electrode tab at an edge of a case that is a sealing portion.
Also, the electrode tab protruding from the case is welded to the external electrode lead. The electrode tab is coupled to the external electrode lead, which is located at a separate space outside the sealing portion of the case. Here, a separate space may be required, regardless of the capacity of the battery. The separate space ranges from about 15% to about 30% of the total volume of the battery pack. Accordingly, the total capacity of the battery may be reduced.
Additionally, the combination structure of the electrode tab and the external electrode lead has a mechanical safety limitation. The electrode tab and the external electrode lead are typically coupled by a welding method. Since a welding portion of the electrode tab and the external electrode lead is exposed to the outside of the case, the welding portion may be easily separated by contact with other components or external impacts.